My autistic child suddenly feels cold, becomes hypotonic and unresponsive with toe‑walking and arm‑flapping—what could be causing this and what emergency actions should I take?

Emergency Assessment of Acute Hypotonia and Unresponsiveness in an Autistic Child

This presentation—sudden coldness, hypotonia (floppiness), and unresponsiveness—represents a medical emergency requiring immediate evaluation for life-threatening conditions, not a typical autism manifestation. While toe-walking and arm-flapping are common autism features, the acute onset of cold extremities with hypotonia and altered responsiveness demands urgent assessment for seizure, metabolic crisis, or toxidrome 1.

Immediate Emergency Actions

Call emergency services (911) immediately and assess airway, breathing, and circulation while awaiting transport. 1

• Check vital signs: Measure temperature, heart rate, blood pressure, and respiratory rate to identify fever, hypothermia, tachycardia, hypertension, or bradypnea 1
• Assess level of consciousness: Use AVPU (Alert, Voice, Pain, Unresponsive) or pediatric Glasgow Coma Scale 1
• Check blood glucose: Hypoglycemia can cause altered mental status and hypotonia in any child 1
• Observe for seizure activity: Postictal states can present with hypotonia and unresponsiveness; note any eye deviation, rhythmic movements, or incontinence 1

Critical Differential Diagnoses to Consider

Seizure or Postictal State

• Epilepsy occurs in 20-25% of children with autism, making this a high-probability diagnosis 1, 2
• Postictal states commonly present with hypotonia, altered consciousness, and autonomic changes (coldness, pallor) 1
• Even without witnessed convulsions, non-convulsive status epilepticus or complex partial seizures can cause unresponsiveness 1

Drug Toxicity Syndromes

Four major toxidromes can present with altered mental status, autonomic dysfunction (coldness), and neuromuscular abnormalities (hypotonia): 1

• Serotonin syndrome: Can occur if the child takes SSRIs or other serotonergic medications; presents with altered mental status, autonomic instability, and neuromuscular changes 1
• Neuroleptic malignant syndrome: Relevant if the child takes antipsychotics (risperidone, aripiprazole); characterized by hyperthermia, rigidity (though early stages may show hypotonia), and altered consciousness 1
• Anticholinergic toxicity: Causes altered mental status, hyperthermia, and autonomic changes 1
• Sympathomimetic toxicity: Presents with agitation, hyperthermia, and tachycardia 1

Metabolic or Endocrine Crisis

• Hypothyroidism, hypoglycemia, or inborn errors of metabolism can cause acute decompensation with hypotonia and altered consciousness 1
• Metabolic disorders (e.g., homocystinuria) are part of the differential for autism-like presentations and can cause acute crises 1

Infectious Causes

• Encephalitis or meningitis must be excluded, particularly if fever is present 1
• Sepsis can cause cold extremities, hypotonia, and altered consciousness 1

What Emergency Providers Need to Know

Inform emergency responders that your child has autism and provide this critical information: 1

• Current medications: Especially antipsychotics (risperidone, aripiprazole), SSRIs, stimulants, or any recent medication changes 1
• Baseline behaviors: Clarify that toe-walking and arm-flapping are baseline autism features, but the coldness, floppiness, and unresponsiveness are new 2, 3
• Seizure history: Report any prior seizures or EEG abnormalities, as epilepsy risk is substantially elevated in autism 1, 2
• Recent illness or injury: Note any fever, vomiting, head trauma, or ingestions 1
• Communication strategies: Explain how your child typically communicates and what calms them, as this will be crucial once they regain consciousness 1

Hospital Evaluation Priorities

The emergency department should perform: 1

• Comprehensive metabolic panel and blood glucose to identify metabolic derangements 1
• EEG if seizure suspected, particularly given the 20-25% epilepsy prevalence in autism 1
• Toxicology screen if medication exposure or ingestion is possible 1
• Neuroimaging (CT or MRI) if focal neurologic findings, trauma, or concern for structural lesion 1
• Lumbar puncture if infectious encephalitis or meningitis cannot be excluded 1
• Thyroid function tests if hypothyroidism is suspected 1

Critical Pitfalls to Avoid

Do not attribute acute medical symptoms to autism itself. 1

• Diagnostic overshadowing is the tendency to attribute all symptoms to the known autism diagnosis, potentially missing serious comorbid conditions 1, 4
• While autism involves social-communication deficits and repetitive behaviors, acute changes in consciousness, tone, and temperature regulation are medical emergencies, not autism features 2, 3, 5
• The baseline autism features (toe-walking, arm-flapping) should not distract from the acute presentation of hypotonia and unresponsiveness 2, 3

Environmental Modifications During Recovery

Once medically stable, implement autism-sensitive care strategies: 1

• Use a quiet room with dimmed lighting to reduce sensory overstimulation 1
• Involve parents as "interpreters" to identify what calms the child and what triggers distress 1
• Consider visual communication systems if the child has limited verbal communication 1
• Minimize unnecessary procedures and personnel to reduce anxiety 1

Follow-Up Considerations

After the acute crisis resolves, coordinate comprehensive evaluation: 1

• Neurology consultation for EEG and seizure management if indicated, given the high epilepsy prevalence in autism 1
• Genetics evaluation if not previously completed, as chromosomal microarray yields diagnostic results in 24% of autism cases and may identify metabolic conditions 1, 4
• Medication review with psychiatry if the child takes psychotropic medications, to assess for drug interactions or toxicity 1
• Sleep study if sleep disturbances are present, as these affect over 50% of individuals with autism and can contribute to medical complications 4